Draw tape bag with side seal attached elastic strip

ABSTRACT

The bag includes a draw tape that may be used to cinch closed the opening of the bag. The bag may include at least one stretched elastomeric strip attached to the bag edges or the ends of the draw tape in an extended condition. In one embodiment, the draw tape is elastic and is attached to the bag edges.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to bags having a draw tape. More particularly, the present invention relates generally to trash bags having a draw tape.

2. Description of the Related Art

Among their many applications, it is known to use thermoplastic bags as liners in trash or refuse receptacles. Trash receptacles that employ such liners may be found at many locations, such as, from small household waste baskets and kitchen garbage cans. The trash canisters are typically made from a rigid material such as metal or plastic. Bags that are intended to be used as liners for such refuse containers are typically made from low-cost, pliable thermoplastic material. When the receptacle is full, the thermoplastic liner actually holding the trash can be removed for further disposal and replaced with a new liner. To avoid inadvertently spilling the contents during disposal, the bags may be provided with a draw tape that allows for constricting or closing the open circumference of the bag. The draw tape may also be tied into a knot to simplify handling of the bag during disposal.

When being utilized as a trash canister liner, it is important that the bag be easily secured into the canister and as the full bag is removed that the open top part of the bag can be easily closed over the contents. U.S. Pat. No. 6,939,042 to Rusnak et al. discloses a plastic bag with a live elastic strip that contracts to restrict the opening. Another potential difficulty is securing the bag to a canister which is larger than the bag mouth opening. If the canister is larger than the bag mouth opening, then the user cannot fold the bag over the rim of the canister. U.S. Pat. No. 6,059,458 to Belias et al. describes a drawtape bag where the drawtape section is gathered into one or more loops defining a series of crests and troughs, and each trough is sealed to the elastomeric strip. The elastomeric strip allows the mouth of the bag to be drawn over the upper portion of a trash container.

However, consumers still may have trouble understanding how to insert stretchy top bags into trash containers. Therefore, it is desirable to develop a method of inserting and securing trash bag liners to trash canisters that makes the “can grip” functionality intuitively obvious. It is also desirable to implement the inserting and securing method in such a manner that it is inexpensive and may be facilitated in a high speed manufacturing environment.

BRIEF SUMMARY OF THE INVENTION

In accordance with the principles of the present invention, in one embodiment, a draw tape bag comprises a first sidewall; a second sidewall, the second sidewall joined to the first sidewall by a closed bottom end, a first edge, and a second edge, thereby defining an open top end having a top surface with a top length; at least one of the sidewalls forming a hem having a top length and extending along the open top end disposed opposite the bottom end having a bottom length, the hem including one or more draw tape notches; a pliable thermoplastic draw tape in an extended state housed within the hem; a strip of elastic material having a fully relaxed length and a stretched expanded length, the elastic strip in the stretched expanded length condition attached to the bag by end seals at the first and second edges of the bag wherein the elastic strip is not attached to the bag or attached to the draw tape at any intermediate points between the first and second edges.

In an embodiment, a draw tape bag comprises a first sidewall; a second sidewall, the second sidewall joined to the first sidewall by a closed bottom end, a first edge, and a second edge, thereby defining an open top end having a top surface with a top length; at least one of the sidewalls forming a hem having a top length and extending along the open top end disposed opposite the bottom end having a bottom length, the hem including a draw tape notch at each end of the hem at the first and second edges; a pliable thermoplastic draw tape in an extended state housed within the hem and having first and second ends; a strip of elastic material having a fully relaxed length and a stretched expanded length, the elastic strip in the stretched expanded length condition within the hem and attached to the draw tape by seals at the first and second ends of the draw tape wherein the elastic strip is not attached to the bag or attached to the draw tape at any intermediate points between the first and second edges.

In one embodiment, the draw tape bag comprises a first sidewall; a second sidewall, the second sidewall joined to the first sidewall by a closed bottom end, a first edge, and a second edge, thereby defining an open top end having a top surface with a top length; at least one of the sidewalls forming a hem having a top length and extending along the open top end disposed opposite the bottom end having a bottom length, the hem including one or more draw tape notches; an elastic draw tape in an extended state housed within the hem and attached to the bag in an stretched expanded length condition by end seals to the first and second edges of the bag wherein the elastic strip is not attached to the bag or attached to the draw tape at any intermediate points between the first and second edges.

The thermoplastic bag may be produced in a high speed manufacturing process that develops continuous sheet-like webs of thermoplastic material into the finished bag via automated equipment. The process may form hems along an edge of the advancing web for accommodating the draw tape. The process may provide a strip of tape material in a relaxed or pre-stretched condition, insert the strip into the hem, and form the side seals in the relaxed or pre-stretched condition. The process may provide a strip or strips of elastic material in a stretched state that is attached to the tape material and/or the hem. The stretched elastic material may be relaxed after or during the manufacture of the rest of the bag.

An advantage is that the elastic characteristic added to the hem or the draw tape enables the bag opening to stretched to fit over and grip the rim of a typical kitchen trash can. It may better secure itself to the container and may resist falling into the container. A gathered hem is intuitively obvious that it will grip the container. Another advantage of the thermoplastic bag is that it includes a draw tape that may be used to constrict the opening and reduce spillage of any contents. Another advantage is that the user may be able to stretch the bag opening to secure the bag to a canister which is larger than the bag mouth opening. These and other advantages and features of the thermoplastic bag will become apparent from the following description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing aspects and others will be readily appreciated by the skilled artisan from the following description of illustrative embodiments when read in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view of a thermoplastic bag having a draw tape in a contracted state that partially constricts the bag opening.

FIG. 2 is a cross-sectional view of the thermoplastic bag taken along line 3-3 of FIG. 1 and illustrating a draw tape accommodated in a hem.

FIG. 3 is a partial cut away view of the thermoplastic bag showing the draw tape and elastic strip attached to the bag.

FIG. 4 is a partial cut away view of the thermoplastic bag showing the draw tape and elastic strip attached to the bag.

FIG. 5 is a partial cut away view of the thermoplastic bag showing the draw tape and elastic strips in the relaxed condition attached to the bag.

FIG. 6 is a partial cut away view of the thermoplastic bag showing the draw tape material and two stretched elastic strips attached to the bag.

FIG. 7 is a partial cut away view of the thermoplastic bag showing the draw tape material and a stretched elastic strip attached to the bag.

FIG. 8 is a partial cut away view of another embodiment of the bag having end cutout notches and the draw tape material and an attached stretched elastic strip.

FIG. 9 is a partial cut away view of another embodiment of the bag having end cutout notches and the draw tape material in the hem and an attached stretched elastic strip attached below the hem.

FIG. 10 is a partial cut away view of another embodiment of the bag having an elastic draw tape attached at end seals.

DETAILED DESCRIPTION

Reference will now be made to the drawings wherein like numerals refer to like parts throughout. For ease of description, the components of this invention are described in the normal (upright) operating position, and terms such as upper, lower, horizontal, top, bottom, etc., are used with reference to this position. It will be understood, however, that the components embodying this invention may be manufactured, stored, transported, used, and sold in an orientation other than the position described.

Figures illustrating the components of this invention show some conventional mechanical elements that are known and that will be recognized by one skilled in the art. The detailed descriptions of such elements are not necessary to an understanding of the invention, and accordingly, are herein presented only to the degree necessary to facilitate an understanding of the novel features of the present invention.

All publications, patents and patent applications cited herein, whether supra or infra, are hereby incorporated by reference in their entirety to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference.

As used herein and in the claims, the term “comprising” is inclusive or open-ended and does not exclude additional unrecited elements, compositional components, or method steps. Accordingly, the term “comprising” encompasses the more restrictive terms “consisting essentially of” and “consisting of”.

The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein may be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although a number of methods and materials similar or equivalent to those described herein can be used in the practice of the present invention, the preferred materials and methods are described herein.

Referring to FIG. 1, there is illustrated a thermoplastic bag 100 of the kind useful as a liner for trash receptacles and refuse containers. Of course, the illustrated bag may have additional or different uses. The bag 100 may be made from a first sidewall 102 and opposing second sidewall 104 overlaid and joined to the first sidewall to define an interior volume 106 for holding trash. The first and second sidewalls may have matching rectangular or square shapes and may be joined along a first side edge 110, a second side edge 112 that may be parallel to and spaced apart from the first side edge, and a closed bottom edge 114 that extends between the first and second side edges. The sidewalls 102, 104 may be joined along their edges by any suitable joining process such as, for example, heat sealing in which the thermoplastic material bonds or melts together. Other sealing or joining processes may include ultrasonic methods and adhesive.

The first and second sidewalls 102, 104 may be made of flexible or pliable thermoplastic material formed or drawn into a smooth, thin-walled web or sheet. Examples of suitable thermoplastic materials may include polymers, for example, polyethylenes (such as, high density polyethylene, low density polyethylene, linear low density polyethylene, very low density polyethylene, ultra low density polyethylene, metallocene based linear low density polyethylene), polypropylene, ethylene vinyl acetate, nylon, polyester, ethylene vinyl alcohol, ethylene-methyl acrylate, or polystyrene, PLA and other degradable based materials, and may be formed in combinations and in single or multiple layers. When used as a garbage can liner, the thermoplastic material will typically be opaque but could also be transparent, translucent, or tinted. Furthermore, the material used for the sidewalls may provide a fluid barrier, such as, a liquid barrier and/or a gas barrier and may include other features such as being treated with deodorants and/or disinfectants as is sometimes desirable in the production of trash can liners.

To access the interior volume 106, the top edges 120, 122 of the first and second sidewalls between the first and second side edges and which are located opposite the bottom edge 114 may remain un-joined to provide the periphery of an opening 124. When the bag 100 is placed in a trash receptacle, the top edges 120, 122 corresponding to the opening 124 are typically folded back over the rim to help retain the bag in a vertical position within the receptacle.

To close the opening 124 of the bag 100 when, for example, disposing of the trash receptacle liner, the bag may be fitted with a draw tape 130. To accommodate the draw tape 130, referring to FIG. 2, the top edges 120, 122 of the first and second sidewalls 102, 104 corresponding to the periphery of the opening 124 may include respective first and second hem flaps 140, 142. The first hem flap 140 may be folded back into the interior volume 106 and attached to the interior surface of the first sidewall 102 to form a first hem 144. Similarly, the second hem flap 142 of the second sidewall 104 is similarly folded back into the interior volume 106 and attached to the second sidewall to form a second hem 146. The hem flaps may be attached to the interior surfaces of the sidewalls by adhesive, heat seals or otherwise. In other embodiments, the hems may be formed by folding the hem flaps toward the exterior of the sidewalls and attaching them to the sidewall exterior surface, or the hems may be formed as separate elements that are attached to the sidewalls. To access the draw tape 130, as illustrated in FIG. 1, first and second notches 147, 148 may be disposed through the respective first and second top edges 120, 122, for example the notches may be centered along the hem between the first and second edges. Pulling the draw tape 130 through the notches 147, 148 constricts the top edges 120, 122 thereby drawing closed the opening 124.

Referring to FIGS. 2 and 3, the draw tape 130 may be formed as an elongated strip of thermoplastic material. When inserted into the hems 144, 146, the draw tape first and second ends 131, 132 may be attached to the first and second sidewalls 102, 104 at the respective first and second side edges 110, 112 while the intermediate section 133 may extend loosely through the first and second hems 144, 146 proximately along the first and second top edges 120, 122. In those embodiments in which the bag is heat sealed together, the draw tape first and second ends 131, 132 may be heat sealed to and in-between the first and second sidewalls 102, 104 at the respective first and second edges 110, 112 to form a side seal. An expanded stretched elastic strip 150 may be inserted in the hem and attached to the fully extended draw tape 130 at the opposite first and second ends 131, 132 but not at any intermediate points in between. The extended draw tape 130 and expanded elastic strip 150 have length 161 between opposite first and second ends 131, 132. The length 161 is equal to the bottom length 160. Referring to FIG. 4 showing a stretched elastic strip 150 is attached to first end 136 and second end 137 below the hems 144, 146. The extended draw tape 130 and the stretched elastic strip 150 have length 161 equal to the bottom length 160. In other embodiments, the extended draw tape and stretched elastic strip have a length longer than the bottom length. FIG. 5 shows that when the draw tape 130 with the attached elastic strip 150 at the top of bag 100 within the hem of FIG. 3 is allowed to relax, so that the elastic strip 150 is allowed to relax into the unstretched condition, the top of the bag 100 and the hems 144, 146 gather so that the relaxed top length 162 is shorter than the bottom length 160. Similarly, the top of the bag in FIG. 4 will also gather when the elastic strip 150 is allowed to relax.

In another embodiment in FIG. 6, the extended draw tape 130 is in the hems 144, 146 and sealed with side seals at 131, 132. There are two expanded elastic strips 152, 153. Elastic strip 152 is attached at side seal 136 and intermediate seal 138. Elastic strip 153 is attached at side seal 137 and intermediate seal 139. In another embodiment in FIG. 7, the extended draw tape 130 is in the hems 144, 146 and sealed with side seals at 131, 132. There is one expanded elastic strip 154. Elastic strip 154 is attached at intermediate seal 138 and intermediate seal 139.

In another embodiment in FIG. 8, only the draw tape ends 131, 132 may be attached together to form a closed loop that is freely accommodated in the hems 147, 148. The draw tape 130 may be accessed through the first and second end notches 149. Pulling the draw tape 130 through the notches 149 constricts the top edges 120, 122 thereby drawing closed the opening 124. One length of expanded stretched elastic strip 150 is attached to first end 131 and second end 132 without attachment at any intermediate points. The expanded stretched elastic strip can be attached to a second expanded stretched elastic strip on the other side of the bag or there may be no expanded elastic strip on the other side. The extended draw tape 130 with the expanded stretched elastic strip 150 has length 161 equal to the bottom length 160. Referring to FIG. 9, an expanded stretched elastic strip 150 may be attached to the first and second ends 136, 137 below the hems 144, 146 without attachment at intermediate points. The extended draw tape 130 with the expanded stretched elastic strips 150 has length 161 equal to the bottom length 160.

In another embodiment in FIG. 10, the draw tape 170 is elastic and stretched and is inserted within hems 144, 146 and sealed with side seals 131, 132 without sealing to the bag or hem at any intermediate points. Similarly, the top of the bag in FIG. 10 will also gather when the elastic draw tape 170 is allowed to relax.

The elastic draw tape or strip can be made from any suitable material, such as, HDPE, HMW HDPE, MDPE, EVA (ethylene-vinyl acetate co-polymer), VLDPE (very low density polyethylene), linear low density polyethylene, Lycra® by DuPont, EPDM (ethylene propylene diene monomer rubber), and rubber, for example.

To provide the elastic characteristic, the draw tape may also be stretched prior to insertion in the hem. Pre-stretching may modify the elastic quality, for instance to change from relatively non-elastic to relatively elastic, of the draw tape allowing expansion and contraction and may facilitate stretching of the draw tape by a consumer during insertion of the bag into a receptacle. Pre-stretching may be accomplished by placing the draw tape under tension such as by pulling the ends of the draw tape to stretch it along its length. After insertion into the hem and attachment to the bag, the stretched draw tape may then be allowed to recover, at least in part, towards its original length. Recovery of the stretched tape may partially constrict the opening in a similar fashion to the above described embodiments of the bag. Thus, the pre-stretched tape is easier to stretch and expand when attaching to a container. Another possible advantage of pre-stretching the draw tape is that the pre-stretched draw tape retains or increases its tensile strength per unit thickness in the direction of stretch. Prestretching draw tape to a greater length enables a greater quantity of draw tapes to be made from a single roll of draw tape material resulting in cost savings of material. In other embodiments, the pre-stretched draw tape may also be imparted with a pattern to modify the elastic characteristics.

Exemplary embodiments are described herein. Variations of those embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventor(s) expect skilled artisans to employ such variations as appropriate, and the inventor(s) intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context. 

1. A draw tape bag comprising: a first sidewall; a second sidewall, the second sidewall joined to the first sidewall by a closed bottom end, a first edge, and a second edge, thereby defining an open top end having a top surface with a top length; at least one of the sidewalls forming a hem having a top length and extending along the open top end disposed opposite the bottom end having a bottom length, the hem including one or more draw tape notches; a pliable thermoplastic draw tape in an extended state housed within the hem; a strip of elastic material having a fully relaxed length and a stretched expanded length, the elastic strip in the stretched expanded length condition attached to the bag by side seals at the first and second edges of the bag; wherein the elastic strip is not attached to the bag or attached to the draw tape at any intermediate points between the first and second edges.
 2. The draw tape bag of claim 1, wherein the elastic strip is attached below the hem.
 3. The draw tape bag of claim 1, wherein the elastic strip is attached within the hem.
 4. The draw tape bag of claim 1, wherein the bag comprises a draw tape notch centered along the hem between the first and second edges.
 5. The draw tape bag of claim 1, wherein the length of the extended draw tape and the stretched expanded length of the elastic strip is equal to the bottom length of the bag.
 6. The draw tape bag of claim 1, wherein both sidewalls form a hem and a draw tape in an extended length is housed within each hem
 7. A draw tape bag comprising: a first sidewall; a second sidewall, the second sidewall joined to the first sidewall by a closed bottom end, a first edge, and a second edge, thereby defining an open top end having a top surface with a top length; at least one of the sidewalls forming a hem having a top length and extending along the open top end disposed opposite the bottom end having a bottom length, the hem including a draw tape notch at each end of the hem at the first and second edges; a pliable thermoplastic draw tape in an extended state housed within the hem and having first and second ends; a strip of elastic material having a fully relaxed length and a stretched expanded length, the elastic strip in the stretched expanded length condition within the hem and attached to the draw tape by seals at the first and second ends of the draw tape; wherein the elastic strip is not attached to the bag or attached to the draw tape at any intermediate points between the first and second edges..
 8. The draw tape bag of claim 7, wherein the draw tape forms a closed loop that is freely accommodated in the hems and not attached to the hems or the bag side walls.
 9. The draw tape bag of claim 8, wherein the bag comprises a draw tape notch at each end of the hem at the first and second edges.
 10. The draw tape bag of claim 7, wherein the bag comprises a draw tape notch at each end of the hem at the first and second edges.
 11. The draw tape bag of claim 7, wherein the length of the extended draw tape and the stretched expanded length of the elastic strip is equal to the bottom length of the bag.
 12. A draw tape bag comprising: a first sidewall; a second sidewall, the second sidewall joined to the first sidewall by a closed bottom end, a first edge, and a second edge, thereby defining an open top end having a top surface with a top length; at least one of the sidewalls forming a hem having a top length and extending along the open top end disposed opposite the bottom end having a bottom length, the hem including one or more draw tape notches; an elastic draw tape in an extended state housed within the hem and attached to the bag in an stretched expanded length condition by side seals to the first and second edges of the bag; wherein the draw tape is not attached to the bag at any intermediate points between the first and second edges.
 13. The draw tape bag of claim 12, wherein the bag comprises a draw tape notch centered along the hem between the first and second edges.
 14. The draw tape bag of claim 12, wherein the length of the extended draw tape is equal to the bottom length of the bag.
 15. The draw tape bag of claim 12, wherein both sidewalls form a hem and an elastic draw tape in an extended length is housed within each hem.
 16. A draw tape bag comprising: a first sidewall; a second sidewall, the second sidewall joined to the first sidewall by a closed bottom end, a first edge, and a second edge, thereby defining an open top end having a top surface with a top length; at least one of the sidewalls forming a hem having a top length and extending along the open top end disposed opposite the bottom end having a bottom length, the hem including one or more draw tape notches; a draw tape in an extended state housed within the hem; wherein an elastic strip is attached to the bag below the hem.
 17. The draw tape bag of claim 16, wherein the draw tape is attached to the bag in an stretched expanded length condition by side seals to the first and second edges of the bag.
 18. The draw tape bag of claim 16, wherein the elastic strip is attached to the bag at a side seal and at an intermediate seal.
 19. The draw tape bag of claim 16, wherein the elastic strip is attached to the bag at two intermediate seals. 